Being single, watching his old friends move on with life- having kids, making mortgage payments; adult activities- isn’t what bummed him out. Being single itself isn’t a big deal to him either. He just can’t help feel the pangs of loneliness as couples embrace along the Manhattan streets. Everyone falling in love, making love all around him; inspiration for his work. No substitute for experience, however.
So while he occasionally hates the single life it wasn’t always for the sake of cradling a warm body, to keep his insecurities in check. Sometimes it’s necessary for his work to make sense.